Method of and means for tying knots



June 17, 1941. NOLING 2,246,218

METHOD OF AND MEANS FOR TYING KNO'IS Filed April 10, 1939, 2 Sheets-Sheet 1 'INVENTQR Martin N. Nolih 53 59 3.7 ATTORNEYS June 17, 19.41- M. N. NOLING METHOD OF AND MEANS FOR TYING KNOTS Filed April 10, 1939 2 Sheets-Shet 2 Fig.8.

INVENTOR Martin N. Noll/13 -B K ATTORNEYS Patented June 17, 1941 METHOD OF AND MEANS FOR TYING KNOTS Martin N. Noling, Rockford, Ill., assignor to Barber-Colman Company, Rockford, 111., a corporation of Illinois Application April 10, 1939, Serial No. 266,941

24 Claims.

The invention relates to an improved method of knot tying as well as to a knotter or knot tying implement therefor. 1

In some respects the present invention is an improvement upon that disclosed in my copending application Serial No. 246,338 filed December 17, 1938. Said copending application discloses a method and apparatus for uniting two or more strands of thread or yarn by tying them in the form of a so-called figure 8 knot. Such a figure 8 knot has been found to be better adapted to unite strands of silk, celanese, rayon or wool than are the round knots tied by such devices as the knotter disclosed in Howard D. Colman Patent No, 755,110, issued March 22, 1904. The present method and apparatus are adapted to unite a pair of threads in a novel form of knot which ties them even more firmly than does a figure 8 knot and, hence, is particularly desirable for use in tying together strands of such material as silk. celanese, rayon or wool.

The particular form of knotter illustrated in said Colman patent, referred to above, is arranged to be strapped to an operator's hand and actuated by a thumb fork or trigger. Although the knot tying mechanism herein disclosed is also illustrated as being of this manually supported and digitally operated type it may, however, be incorporated in other types of mechanisms such as a warp tying or warp uniting machine and may be either hand or power operated.

The general object of the present invention is to provide a novel method of and apparatus for knotting together a pair of threads in a novel form of knot by virtue of which a tight strong knot is formed between threads of even such materials as silk, rayon, celanese or wool, as well as more easily knotted materials such as cotton.

More specifically, an object of the invention isto provide a novel method of forming what may be termed an interlocked figure 8 knot in a pair of thread strands so as to firmly and permanently unite the same, this novel method of knot formation being of such character that it can be readily carried out by a mechanical knotter.

Still another object is to provide an improved knotter capable of quickly and accurately tying a plurality of threads in theform of my novel interlocked figure 8 knot.

Further objects and advantages of the invention will become apparent as the following description proceeds taken in connection with the accompanying drawings in which:

Figure 1 is a plan view of a knotter embodying the invention and adapted to carry out the improved method of knotting herein disclosed.

Fig. 2 is an end elevation of the knotter of Fig. 1.

Fig. 3 is also an end elevation of the knotter of Fig. 1, but as viewed from the opposite end from that of Fig. 2, and with the supporting handle structure broken away.

Fig. 4 is a partial vertical sectional view along the line 4-4 of Fig. 1.

Fig. 5 is an enlarged partial front elevation of the knotter.

Fig. 6 is an enlarged detail view, partly in section along the line 6-6 of Fig. 1, of the thread guide mechanism.

Fig. 7 is an enlarged developed view of an actuating cam and segmental gear included in the knotter.

Fig. 7 is a detail view ofa safety catch device for one of the thread guides.

Figs. 8 to 14, inclusive, are fragmentary stop motion views of the knotter mechanism showing successive steps in the knot tying cycle.

Fig. 15 is a detail view of the knot before the loops are drawn tight.

Fig. 16 shows the completed knot after it has been tightened.

Briefly stated, the novel method of knot tying herein contemplated includes the steps of forming a doubly twisted loop in one thread, a singly twisted loop in a second thread and then drawing adjacent end portions of the threads through both loops to complete the final unitary knot.

By the term singly twisted loop reference is made to a loop in which the thread forming it is crossed over itself once at the base of the loop, while the term doubly twisted loop refers to a loop in which the thread forming it is crossed over itself at the base of the loop and then one strand twisted about another in the manner accomplished when a singly twisted loop is rotated through substantially ina direction to further twist the strands at the base of the loop. When the threads are manipulated in the manner noted they lie in the configuration shown in Fig. 15 and when thereafter pulled tight the'completed knot in Fig. 16 is achieved. For convenience, this novel form of knot has been termed herein an interlocked figure 8 knot. This designation has been chosen since the threads are arranged in a manner roughly resembling a figure 8 knot but differing therefrom in that the threads are better interlocked than in a conventional figure 8 knot:

For purposes of analysis of the novel interlooped identically with each other and each in the form of a figure 8 knot. InFig. 15 herein the'two knotted threads a and b are shown in black and whiterespectively to facilitate their identification. It will be seen that the black thread a is arranged in the form of a conventional figure 8 knot. On the other hand the white thread b which is interlocked with the thread a is arranged, not in the form of a figure 8 knot, but in that of a round knot. By thus forming a round knot in one thread and leading its ends through the loops of a figure 8 knot in the other thread, in the manner illustrated in Fig. 15, a highly eifective interlocking of the threads is accomplished.

The novel interlocked figure 8 knot herein disclosed lends itself particularly well to formation by means of a rotating bill type of knotter mech-' anism. This is for the reason'that a round knit can be formed by rotation of a knotting bill through roughly one revolution while a figure 8 knot can be formed by rotation of a tying bill through roughly two revolutions. Accordingly. the knot formations in the two threads can be accomplished by a single tying bill with one thread engaged by the tying bill through sub: stantially two revolutions and the other one through only about one revolution. When thus formed more or less simultaneously by a. single tying bill the knot formations in the threads are intertwined in the manner required to ac complish my novel interlocked figure 8 knot.

The knotter mechanism herein disclosed is generally similar to that of my said copending application No. 246,338 in that it also embodies a knotter bill rotatable through substantially two revolutions for each knot formed since that is also required in uniting a pair of threads by a figure 8 knot. The present knotter differs from that of my copending application, however, in

a bill spring 28 presses the pivoted shear blade against the fixed blade [8. On the butt end of the pivoted shear blade i8 is fashioned a cam enlargement 2| (Figs. 4 and 5) fitted within a generally heart shaped cam aperture 22 fashioned in a nonrotatable cam barrel 23. This cam barrel is, in turn, secured to an extension 24 on the standard l8.

As the knotter shaft i1 is rotated the tying bill ll rotates correspondingly and the Jaws or blades i8 and I8 move to their open and closed positions in timed relation with the knotter shaft rotation In particular, .the contour of the cam aperture 22 is preferably such that beginning with the blades pointing upwardly (as shown in Figs. i and 5) the pivoted blade l8 swings from a partially open position to a fully open position as the bill rotates clockwise (as viewed from the outer end) and is, in general, open through substantially 180 of rotation, after which it closm for the succeeding 180 of rotation. The tying bill construction is substantially like that shown in said Colman Patent No. 755,110 and, consequently, further detail of description is believed to be unnecessary.

Rotation of the knotter shaft H isaccomplished by means of a thumb fork or trigger 25 (Figs. 2, 3 and 4). This fork is secured by a split-sleeve clamp 28 (Fig. 3) to a sleeve 21 (Fig. 3) journaled on the pin H. An enlarged head on the outer end of the pin ll prevents endwise displacement of the sleeve 21. Integral with the inner end of the sleeve 21 is a segmental gear 28 meshing with a skew pinion 29 (Fig. 4) fast on the knotter shaft l7. Consequently, when the actuator fork 25 is oscillated downwardly (from the initial position shown in Fig. 4) the sector gear 28 causes the pinion 29, and attached knotter shaft H, to rotate in a clockwise direction (Fig. 5) through approximately two revolutions. For a purpose which will hereinafter appear, an integral sector cam 30 (Figs. 1 and 7) that provision is made for locating and shifting the threads separately to present them to the knotter bill in timed relation to its rotation and in such manner as to accomplish the different looping of the individual threads required for my interlocked figure 8 knot.

In the particular construction shown the mechanism is mounted on an upright standard Iii (Fig. 3) having a transversely extending pin l l which is fixed to its lower end. Adiustably fixed to one end of this'pin it, by a split-sleeve clamp i2, is an inverted L-shaped supporting handle i3. A flexible strap i4 is secured to this handle i3 in such manner that it can be readily buckled about an operator's left hand to support the device while leaving the thumb of the hand free to actuate the knotter. This supporting arrangement is substantially the same as that shown, for example, in Fig. l of said Colman Patent No. 755,110.

The knotter embodies atying bill, designated generally by the numeral 13 (Figs. 1 and 4), which is rotated through substantially two revolutions in each knot tying cycle. In the construction illustrated, the tying bill includes a fixed blade l6 (Fig. 5) fashioned as an integral lateral extension on the outer end of a rotatable knotter shaft I! (Fig. 4), and a cooperating movable shear blade iii. The movable shear blade I8 is pivoted on the fixed blade at l3, and

having a cam slot 3i therein, is also fixed to the sector gear 28.

Thread guiding means, designated generally by the numerals 32 and 33 (Fig. 1), are located on opposite sides of the tying bill 15. These guide mechanisms may be economically fashioned as sheet metal stampings and each embodies a pair of generally upwardly facing notches or recesses for receiving the threads a and b which are to be tied. To start the knotting operation the thread a is located in notches 34 and 35, formed respectively in the guide members 32 and 33 (Figs. 2 and 3). Similarly the thread b is located in a notch 36 in the guide member 32 and in a notch 31 formed in a U- shaped sheet metal auxiliary guide member 38 pivoted at 39 on the guide member 33. From their initial positions (Figs. 1, 2 and 3) the thread guiding means 32, 33 and 38 are shifted to move and operate upon the threads in a manner which will hereinafter appear.

The thread guide 32 serves to locate the threads in proper angular relation to the tying bill l5 during the knotting operation and also 2,248,218 wise fixed to the outer end of a channel shaped sheet metal supporting arm 48 (Fig. 1) which is in turn pivoted at its inner end on a pin 4| between the ends of a U-shaped bracket 42 screwed to the standard In (Fig; 3). Cooperating with the thread receiving notches 34 and 36 in the stripper 32 is a pair of sheet metal clamping fingers 43 (Figs. 1 and 2) fixed to the end of an arm 44. This arm 44 is reciprocable generally longitudinally of the stripper 32 so that stepped forward noses on the fingers 43 may be moved from the retracted position shown in Fig. 1 forwardly toward the outer end 01' the stripper 32 to clamp the threads a and b in the notches 34 and 36 at the proper time in the knotting cycle. The arm 44 is carried at its inner end by a supporting arm 45 (Fig. 1) journaled on the pin 4i .and pivoted to the arm 44 by a pin 46 (Fig. 2) which extends through a sleeve extension "On the arm 44.

The second thread guide 33 serves toshift the portions of the threads a and b, on its side of the tying bill I 5, in a certain predetermined man"- ner and in timed relation with the rotation of the tying bill. As was previously noted, the tying bill blades l6 and I8 open during each revolution of the bill, but, as will hereinafter appear, it is desirable in tying an interlocked figure-8 knot that the threads should be engaged between the blades only during the second revolution and, furthermore, it is desirable that only one of the two threads should be looped about a the tying bill during the initial part of the latters first revolution. To this end the guide'33 is arranged to have an initial projected position (Fig. 8), which it maintains throughout at least the first half revolution of the tying bill l5, and a retracted position (Fig. 10) which it occupies during substantially the next suceeding revolution and a half of the tying bill. Furthermore, shifting of the thread b from a retracted position out of engagement with the tying bill 15 (Fig. 9)

to a position of operative engagement with it (Fig. 12) is accomplished by swinging the auxiliary guide 38 from the full line position of Fig. 6 to the dot-dash line position shown therein.

To support the guide 33 for longitudinal movement as described above a generally U- shaped sheet metal bracket 48 is utilized (Figs. 1, 5 and 6). This bracket embodies a laterally extending clip 49, which embraces the fixed cam barrel 23 and frictionally engages the same, to hold the bracket in position. Integral ears 5!) on the sheet metal thread guide 33 embrace the outer arm of the bracket 48 so that the thread' guide is supported for reciprocation along this bracket arm.

Actuation of the stripper 32 and thread guide 33, in timed relation with the rotation of the tying bill i5, is accomplished by means of the sector cam 30. A cam follower roller 51 (Fig. 3) carried by one arm 52 of a bell crank 52 (Fig. 1), journaled on the pin 4|, projects within the cam slot 3i. The other arm 52 of this bell crank 52 is connected to the thread guide 33 by a link 53. Similarly, on the other side 01' the knotter the bell crank operates to reciprocate the clamp fingers 43 along the stripper 32 in timed relation with the rotation of the tying bill. This is accomplished by the arm 45. which is rigid with the bell crank 52 and is connected to the arm 44 having the fingers 43 thereon.

The stripper 32 is swung laterally away from the tying bill while maintaining the fingers 43 in clamping relation with the threads in the notches 34 and 36, through a disengageable connection with the arm 45. For this purpose a dog 54 (Figs. 1 and 2) is pivoted on the arm 46 and is yieldably urged by flat spring 55 to a projected position in which it engages the upper end of the pin 46 when the arm 45 and hence the pin is in its forward extremity of movement. This construction is substantially like that for actuating the stripper in said Colman Patent No. 755,110, and reference may be made to it for details 01 construction. Upon the return movement of the pin 46, during oscillation of the arm 45, the dog 54 is engaged by the pin 46, thereby swinging the stripper 32 outwardly about the pivot pin 41. This outward swinging of the stripper continues until the pin 46 reaches substantially the extremity of its return movement at which time the dog 54 rides out of engagement with the pin by virtue of its, contact with a suitable disengaging stop arrangement (not shown in detail). A helical spring 56 (Fig. 2) connected between the arm 40 and the bell crank 52, then snaps the stripper 32 back to its initial position.

In the rotation of the tying bill i5 through two revolutions for one complete knotting cycle, as above mentioned, it occupies successively the position shown in Figs. 8 to 14, inclusive. The corresponding positions of the stripper 32 and thread guide 33 are also shown in these figures.

Oscillation of the auxiliary thread guide 38, which is pivoted on the thread guide 33, is accomplished by a fixed pin 51 (Fig. 6) on the bracket 48 coacting with a slot 58 fashioned in the member 38. When the thread guide 33 is retracted (moved to the left, as viewed in Fig. 6) from its projected position (Figs. 8 and 9) the auxiliary thread guide is drawn rearwardly and the slot 58 engaging with the stationary pin 51 causes the member 38 to be oscillated about its pivot pin 39 in a counterclockwise direction (as viewed in Fig. 6). As a result theright hand portions of the threads a and b (as viewed in Fig. 11) are shifted across each other and positioned between the blades of the tying bill, l5 in the location shown in Fig. 12.

- The parts of the knotter are arranged positively to insure proper location of both the threads as and b in their corresponding guides 33 and 38. Such an arrangement is desirable because if the threads are incorrectly positioned it is possible to tie a plain figure-8 knot in the threads rather than an interlocked figure-8 knot. Accordingly, to prevent actuation of the knotter when the thread b is incorrectly positioned, a sensitive feeler in the form of a latch 59, is pivoted on a stationary pin 48 on the'bracket 43. A latching nose 5i) on the feeler 59 is held in engagement with a notch 68, fashioned on one of the ears 5!) of the movable threadguide, by a light torsion spring 48 (Fig. 6). The latch 59 has a depending arm 59 thereon that is engaged by the thread b when the latter is correctly positioned in the notch 31 so that the latch 59 is depressed (to the dot-dash line position of Fig.

. 6) to clear the notch 60, thereby leaving the knotter free to operate. In the absence of a thread in th notch 31 pressing against the latch arm 59 it is apparent that the nose 59 of the latch 53 will engage the notch 69 and prevent rearward movement of the thread guide, thus efiectually preventing operation of the knotter.

Similarly for insuring proper location of-the thread a, a second sensitive feeler or latch 5| (Fig. 7 is pivoted on the guide 33 by a pin 39.

This latch is urged into engagement with a shoulder 62 on the bracket 48 by a contractile spring 6l When the thread a is properly seated in the root of the guide notch 35 is depresses the outer end of the latch 6| (swings it clockwise as viewed in Fig. 7) to the dot-dash line position shown. In this way the latch Si. is released from the shoulder 62 and the guide 33 freed for reciprocation. Otherwise movement of the guide is stopped and operation of the knotter thu effectually prevented.

The stripper 32 is aided in the final tightening of the knot by a finger 63 on the end of a resillent sheet metal arm 64 screwed to the knotter frame (Fig. 1). As will hereinafter appear in greater detail the knot is tightened by being drawn around the finger 63 as the knot is bein stripped from the tying bill l5.

To condition the knotter for operation, the operator shifts the thumb fork 25 to its uppermost position so that the tying bill I! faces upwardly and the stripper 32 is swung inwardly with the clamp fingers 43 retracted, while the thread guide 33 is in its projected position, all as indicated in Figs. 1 and 5. A pair of threads a and b, which are to be tied, are then laid across the knotter mechanism. The threads are tensioned slightly so that they occupy substantially the position shown in Figs. 1 and and in which the thread a is received in the notches 34 and 35 while the thread b is received in the notches 3'6 and 31. To aid in the location of the threads and to guide them to their respective positions a curved extension finger 55 (Figs. 1 and 5) is formed on the guide 33 to overlie the tying bill 15. The thread a is placed in the knotter by moving it downwardly past the rear edge of the finger 65 (as viewed in Fig. 1) while the other thread b is moved past the forward side of the finger 65 into the notches 36 and 31 which receive it. In moving into position the thread b slides down the front of the finger G5 and over the nose 65 (Fig. 6) at its base and finally into the notch 37. Upon reference to Figs. 1, 5 and 8 it will be seen that the threads 0. and b are located respectively above and below the knotter shaft II which carries the tying bill l5 and furthermore are crossed over each other.

After having thus inserted the threads, all the operator need do in order to tie an interlocked figure-8 knot to unite the threads is simply to depress the actuator fork 25. Such downward movement of. the actuator oscillates the sector cam and sector gear 28 so that the tying bill l5 rotates in a clockwise direction from its initial position of Fig. 5 and the stripper and thread guides are moved in timed relation to it. To facilitate an analysis of the correlated actions of the tying bill and associated guide mechanisms reference should be made to the series of stop motion views (Figs. 8 to 14) which show the parts at progressive stages of tying bill rotation.

In its first 90 of rotation the tying bill I 5 moves from the full line position of Fig. 8 (and also of Fig. 5) to the dot-dash line position of Fig. 8. The bill blades I 6 and I8 are open at this latter point but the threads a and b are held away from th open blades so as not to be received between them. The thread a, however, is held outwardly by the guide 33 so that it will be engaged by the leading side face of the bill l5 during the first 90 of movement and looped about it during the subsequent rotation of the bill.- On the other hand the thread b is held retracted; by the auxiliary guide 38 so that it is completely out of contact with the tying bill during this period.

Upon reaching its position (Fig. 9) the tying bill I! has substantially completed a singly twisted loopor half hitch in the thread a but it has still not yet done any substantial twisting of the other thread b. Furthermore, the blades l3 and I3 are substantially closed at this point. The stripper 32 and thread guides 33 and 33 are still in approximately their initial positions. Upon reference to Fig. 7 it will be seen that the slope of the cam slot 3| is very gradual in the begixming and consequently the actuating bell crank 52 for the tripper and thread guide is oscillated only a small ,amount during the first 180 of bill rotation.

After 270 of rotation (Fig. 10) the tying bill I! has completed a singly twisted loop or half hitch in the thread w and its forward face is pressed against the left hand portion of the thread b preliminary to looping this latter thread. It will be noted that the tying bill blades are closed in this position. The clamping fingers 43 cooperating with the stripper have moved forwardly so that they are just ready to clamp the threads a and b in the corresponding stripper notches 34 and 36. Similarly, at the other side of the knotter the guide 33 has begun its retractive movement so as to draw the thread a into position for subsequent engagement by the bill blades for shearing. This retraction of the guide 33 has oscillated the guide member 38 in a counterclockwis direction (as viewed in Fig. 6) about its pivot 39 so that the notch 31 is thrust forward in its movement to locate the thread b for similar subsequent engagement by the tying bill blades.

After one full revolution of the tying bill l5 (Fig. 11) a doubly twisted loop is nearly complete in the thread a and a. singly twisted loop or half hitch is substantially completed in the thread b. Furthermore, the fingers 43 have clamped the left hand portions of both the threads a and b in the respective notches 34 and 36 on the stripper 32 while the guides 33 and 38 have continued their motions previously described so as to bring the threads a and b still closer together. The bill blades l6 and I8 are at this point ready to begin opening again during the subsequent second revolution.

Upon reaching its 450 position (Fig. 12) the tying bill I5 has completed a doubly twisted loop in the thread a and a singly twisted loop or half hitch in the thread b. Furthermore, the bill blades I 6 and I3 are now open to receive the right hand portions of the threads (1 and b, which are positioned to enter directly between the blades. The stripper clamping fingers 43 remain closed at this point and, in fact, until the knot is complete.

In passing from the position of Fig. 12 to that of Fig. 13 the shear blade l8 of the tying bill l5 closes, thus shearing the right hand portions of both of the threads at and b which were received between the open blades. The sheared ends of the threads, to the left of the tying bill, are firmly clamped between the shear blade l3 and bill spring 20 while the waste end portions remain in the guides 33 and 33. At this point the looping and shearing of the threads has been completed so that to manipulate the threads into the position of Fig. 15 it is only necessary to strip the loops or hitches from the bill I5 while retaining the sheared ends gripped by the bill blades.

. While the tying bill is rotated from the position of Fig. 13 to that of Fig. 14, and in which latter position it has completed substantially 630 of rotation, the stripper 32 is swung laterally in the manner previously described. In this way the thread loops are stripped from the tying bill l5 while the sheared ends are still gripped by it so that in effect the sheared ends are drawn through the loops. It will be noted that the threads a and b pass on opposite sides of the finger 63. Consequently the knot is drawn tight against the finger 63 and finally reaches its completed configuration shown in Fig. 16.- During the final motion of the tying bill ii to its initial upright position the sheared ends of the threads are pulled from between the blades and the stripper 32 is finally permitted to return to its initial position by release of the dog 54 as pre-' viously described. The knotted threads may then be lifted from the mechanism. To condition the knotter for a subsequent knotting cycle it'is, of course, necessary to restore the thumb fork 25 to its initial position shown in Fig. 2.

From the foregoing it will be seen that substantially two full revolutions of the tying bill l5 are utilized to form a doubly twisted loop in the thread a although since the tying bill blades open during each revolution it is necessary to shift the position of the thread a so that it will not be engaged directly between the bill blades except during the second revolution. In this way the thread a is looped in the form of a figure-8 knot as shown in Fig. 15. Simultaneously with the looping of such thread a the thread b is intertwined with it but in the form of a round knot rather than a figure-8 knot. Since it is only necessary to form a singly twisted loop rather than a doubly twisted loop in the thread I) to arrange it in the form of a round knot a single revolution of the tying bill is sufllcient for this purpose. Accordingly it is for this reason that the thread 17 is held out of engagement with the tying bill during most of its first revolution or, in other words, during the time that the initial singly twisted loop is being formed in the thread a.

I claim as my invention:

1. The method of knotting together a pair of threads which comprises, forming a doubly twisted loop in one of the threads, forming a singly twisted loop in the other thread, and drawing a pair of end portions of both of the threads through both loops.

2. The method of knotting together a pair of threads which comprises, forming a singly twisted loop in one of the threads, twisting such loop through substantially 180 to recross the strands at the base of the loop, during such twisting of said one thread twisting the other thread a like amount to form a singly twisted loop therein, and drawing a pair of end portions of both threads through the loops in each of said threads.

3. The method of knotting together a pair of threads which comprises, pressing a tying bill laterally against one only of the threads, rotating the bill through substantially 180 to form a half hitch in said one thread about the bill, locating the other thread into position for engagement by the tying bill, continuing the rotation of the tying bill through substantially a full turn to recross the strands forming the half hitch in said one thread and to form a half hitch in said other thread, and withdrawing the tying bill from the hitches in both of the threads while drawing end portions of both of the threads through the hitches as an incident to the withdrawal of the tying bill therefrom.

4. The method of tying together a pair of threads in an interlocked figure-8 knot which comprises, looping one" of the threads in the form of a figure-l knot, looping the other thread in the form of a round knot with the end portions of said other thread extending through the loops of said figure-8 knot, and drawing both of said knots tight to form a unitary interlocked figure-8 knot.

5. A knot tying mechanism comprising, in combination, means forming a doubly twisted loop in one, thread and forming a singly twisted loop in a second thread, and means associated with the first mentioned means for drawing a pair of end portions of both the threads through both of the loops formed by such first mentioned means.

6. A knot tying mechanism comprising, in combination, means forming a singly twisted loop in one thread and then twisting such loop through substantially to recross the strands at the base of the loop while at the same time forming a singly twisted loop in a second thread, and means associated. with the first mentioned means and drawing a pair of end portions of both threads through the loops in each of the threads formed by said first mentioned means.

7. A knot tying mechanism comprising, in combination, a rotatable tying bill, means associated with said bill and rotating the same through substantially two revolutions, and guide means adjacent said bill and receiving a .pair of threads and locating one of the threads in position to be looped about said bill during a sufiicient portion of the latters movement to form a doubly twisted loop therein while 10- cating the other thread in a position to be twisted by the tying bill in only a singly twisted loop, said tying bill embodying means drawing adjacent end portions of the threads through both loops as an incident to the withdrawal of the loops from the bill.

8. A knot tying mechanism, comprising, in combination, means looping one thread in the form of a figure-8 knot and at substantially the same time looping a second thread in the form of a round knot with the portions of said second thread adjacent such round knot passed through the loops of the figure-8 knot, and means associated with the first mentioned means and tensioning both threads to draw the knotted portions thereof tight in the form of a unitary interlocked figure-8 knot.

9. A knotter comprising, in combination, a rotatable tying bill projecting laterally from the axis of rotation thereof, said tying bill embodying a pair of cooperating blades extending longitudinally thereof and opening toward the outer end thereof, means associated with said tying bill and rotating thesame through substantially two full revolutions, thread guiding means receiving a pair of threads and locating one of the threads in a position to be looped about said bill during a sufiicient portion of the latter's movement to form a doubly twisted loop therein while locating the other thread to be twisted by the tying bill in only a singly twisted loop, said guide means operating upon the completion of such looping operations to shift portions of the threads adjacent the respective loops therein to a position between said blades during the second revolution of said bill, and means pulling both of such loops from said bill while the adjacent portions of the threads are gripped by said blades.

10. A knotter embodying a rotating tying bill provided with a pair of shear blades. and means moving said blades to open and closed positions during each revolution of said bill, and characterized by the provision oi means holding a first thread in a position to be engaged by said bill for looping of the thread during each revolution of the bill and holding a second thread in position to be engaged by the bill for looping of the same during alternate revolutions of said bill while maintaining both of said threads out of engagement with said blades during alternate revolutions of said bill and shifting both of said threads into position between the blades during the other revolutions of the bill.

11. A knotter comprising, in combination, a rotatable tying bill embodying a plurality of pivotally connected blades, actuating means associated with the bill and rotating the same through substantially two revolutions and for opening and closing said blades during each revolution, a pair of movable thread guides adiacent said bill and engaging respective ones of a pair of threads passed over said tying bill, one of said guides having one position in which it holds one of the threads in a position out from between said blades when the'latter are open but in a position to be looped by the bill and a second position in which it holds said one thread between said blades when the latter are open, said other thread guide having one position in which it holds the other thread not only out from between said blades when the latter are open, but also out of position to be looped by said bill and a second position in which it holds such second thread between said blades when the latter are open, and means operating in timed relation with said actuating means positioning both of said thread guides in said first positions thereof for the interval in which said blades are open during the first revolution of said bill and positioning both of said guides in said second positions thereof while said blades are open during the second revolution thereof.

12. A knotter comprising, in combination, a rotatable tying bill embodying a plurality of pivotally connected blades, a thread guiding hook disposed at one side of said bill and reciprocable along a path generally paralleling the axis of rotation of the bill, said hook being reciprocable from an initial position displaced longitudinally of said axis and in which a thread therein is located in position to be engaged by said bill and looped around the same although out from between said blades to a second position in which such thread is located between said blades when the latter are open, a second thread guiding hook pivoted on said first named hook and swingable from a position in which a second thread received therein is positioned not only out from between said blades when they are open, but also out of position to be looped by said bill in its rotation to a second position in which such second thread is located between said blades when the latter are open, means associated with said bill and rotating the same through substantially 'two revolutions and opening and closing said blades during each revolution, and means operating in timed relation with said last named means and shifting both of said hooks from their initial positions to said second positions after said blades have closed from their open position during the first revolution of said bill.

13. A knotter comprising, in combination, a rotatable tying bill, a thread guiding hook disposed at one side of said bill and reciprocable along a path generally paralleling the axis of rotation of said bill, a second thread guiding hook pivoted on said first guiding hook, an abutment located to contact said second hook and swing the same about its pivot during the reciprocation of said first guiding hook, and means rotating said bill and shifting said first guiding hook through a predetermined cycle of reciprocation in timed relation with such rotation of the bill.

14. A knotter comprising, in combination, movable means twisting a plurality of threads in looped configuration for knotting, a thread guide reciprocable in timed relation with said first named means in a path adjacent to the latter, an auxiliary thread'guide, and means shifting said auxiliary thread guide as an incident to movement 01 the first named guide.

15. A knotter comprising, in combination, a rotatable tying bill embodying a pair oi relatively movable shear blades, means opening and closing said shear blades in timed relation with the rotation of said bill, and means locating a pair of threads with portions thereof on opposite sides of said tying bill and operating at a predetermined point in the rotation of said bill to shift both of said threads toward each other into position between the blades for seizure thereby.

16. A knot tying mechanism embodying means twisting a thread in looped configuration for knotting, and means guiding the thread with respect to said first named means, said mechanism being characterized by the provision of means preventing actuation of said first named means except when a thread is located in predetermined position in said guiding means.

17. A knot tying mechanism comprising, in combination, movable means twisting a thread in looped configuration for knotting, a movable thread guide adapted to receive a thread and locate the same with respect to said first named means, a latch for holding said first named means against movement, and means arranged to be actuated by a thread properly positioned in said thread guide to release said latch.

18. A knot tying mechanism comprising, in combination, means twisting a thread in looped configuration for knotting, a guide locating a' thread with respect to said first named means, releasable means preventing actuation of said first named means,-and means including a sensitive feeler, arranged to be actuated by a thread properly located in said thread guide, releasing said actuation prevention means.

19. A knot tying mechanism comprising, in combination, movable means twisting a thread in looped configuration for knotting, a first movable thread guiding hook adjacent the first mentioned means, a second thread guiding hook pivoted on said first hook, a releasable latch holding said hook against movement, means positively interconnecting said first named means and said first hook for movement in timed relation to each other, and means, including a finger engageable by a thread properly located in said second hook, releasing said latch to release for movement said first hook and said first named means which is interconnected therewith.

20. A knot tying mechanism comprising, in

combination, means twisting a pair of threads in looped configuration for knotting, first and second thread guides adjacent the first mentioned means and locating respective ones of the threads with respect to said first named means, a feeler associated with each of said guides and arranged to be actuated by a thread located in predetermined position therein, and means, releasable only by actuation of both of said feelers, conditioning said first named means for operation.

21. A knot tying mechanism comprising, in combination, a rotatable tying bill, a pair of thread guiding hooks located at one side of said bill, and means including an extension finger on the nose of one of said hooks adjacent the other and overlying said tying bill for separating a pair of threads laid thereon and for directing the respective threads into the corresponding guide hooks.

22. A knot tying mechanism comprising, in combination, movable means twisting a thread in looped configuration for knotting, a pair of thread guiding means adapted to receive and locate respective threads in operative relation with respect to said first named means, and means separating a pair of threads laid thereon and directing the respective threads into the corresponding ones of said first named guiding means.

23. A knot tying mechanism comprising, in combination, a rotatable tying bill, a movable stripper engageable with a pair of threads looped about the bill to strip them from it, said stripper being adapted to receive the pair of threads with the portions of the threads located between the tying bill and the stripper arranged in crossed relation, and an auxiliary tensioning finger located between the stripper and bill in position to engage the threads with the crossed portion of the latter located between such finger and the bill and with the threads led from the finger to the stripper on opposite sides of the finger.

24. A knot tying mechanism comprising, in combination, movable means twisting a thread in looped configuration for knotting, means stripping a looped thread from said first named means, and means including a yieldable resilient finger arranged to engage the thread during the stripping operation and tension the same to tighten the knot formed therein.

MARTIN N. NOLING. 

